Jacob Lew says in a statement Tuesday that it is "important that China demonstrate a renewed commitment to move to a more market-determined exchange rate."

Beijing in March widened the narrow band in which it allows the yuan to fluctuate against the U.S. dollar. But it retained controls that critics complain keep the yuan undervalued and give its exporters an unfair price advantage.

In his statement, Lew said Washington also wants a more "open, balanced" trade and investment relationship. He said that would include opening China's markets wider to foreign investment and ensuring equal treatment for all companies.